The DNA polymerase delta complex is involved in DNA replication and repair, and it consists of the proliferating cell nuclear antigen (PCNA), the multisubunit replication factor C, and the 4 subunit polymerase complex: POLD1, POLD2, POLD3, and POLD4.

The enzyme is 94% identical to bovine DNA polymerase delta and contains the numerous highly conserved regions previously observed in the bovine and yeast enzymes. The human enzyme also contains 2 putative zinc finger domains in the C-terminal region of the molecule as well as a putative nuclear localization signal at the N-terminal end.WRN functionally interacts with DNA polymerase delta, which is required for DNA replication and DNA repair.